全文获取类型
收费全文 | 773641篇 |
免费 | 9173篇 |
国内免费 | 2050篇 |
专业分类
电工技术 | 13018篇 |
综合类 | 2896篇 |
化学工业 | 116309篇 |
金属工艺 | 35040篇 |
机械仪表 | 25186篇 |
建筑科学 | 17755篇 |
矿业工程 | 5589篇 |
能源动力 | 18220篇 |
轻工业 | 56373篇 |
水利工程 | 9354篇 |
石油天然气 | 18357篇 |
武器工业 | 50篇 |
无线电 | 81635篇 |
一般工业技术 | 159410篇 |
冶金工业 | 127968篇 |
原子能技术 | 17979篇 |
自动化技术 | 79725篇 |
出版年
2021年 | 6697篇 |
2020年 | 4909篇 |
2019年 | 6378篇 |
2018年 | 24624篇 |
2017年 | 23598篇 |
2016年 | 21130篇 |
2015年 | 8169篇 |
2014年 | 12932篇 |
2013年 | 31202篇 |
2012年 | 22324篇 |
2011年 | 34759篇 |
2010年 | 28220篇 |
2009年 | 28299篇 |
2008年 | 29844篇 |
2007年 | 30228篇 |
2006年 | 19811篇 |
2005年 | 18986篇 |
2004年 | 18341篇 |
2003年 | 18158篇 |
2002年 | 16666篇 |
2001年 | 16312篇 |
2000年 | 15396篇 |
1999年 | 15526篇 |
1998年 | 37756篇 |
1997年 | 26953篇 |
1996年 | 20578篇 |
1995年 | 15657篇 |
1994年 | 13754篇 |
1993年 | 13624篇 |
1992年 | 10178篇 |
1991年 | 9795篇 |
1990年 | 9745篇 |
1989年 | 9393篇 |
1988年 | 8773篇 |
1987年 | 8054篇 |
1986年 | 7858篇 |
1985年 | 8626篇 |
1984年 | 8158篇 |
1983年 | 7418篇 |
1982年 | 6949篇 |
1981年 | 7119篇 |
1980年 | 6864篇 |
1979年 | 6905篇 |
1978年 | 6881篇 |
1977年 | 7783篇 |
1976年 | 9762篇 |
1975年 | 6065篇 |
1974年 | 5909篇 |
1973年 | 5985篇 |
1972年 | 5119篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Summary The oblique flow of a viscous fluid impinging on a flat wall with suction or blowing is studied. It is found that when suction is applied the fluid penetrates the wall while blowing causes the shifting of the stagnation point. It is also found that this shifting depends upon the magnitude of the blowing. 相似文献
992.
N. Realdon M. Dal Zotto E. Ragazzi G. Dalla Fini 《Drug development and industrial pharmacy》1996,22(2):125-134
The release rate of a drug dissolved in the liquid phase of lipogels may be greatly affected by the type and concentration of gelling agent and by processing conditions and mechanical treatment of the ointment. These differences in release rate are reduced after application of mechanical stress comparable with the strain exerted on the ointment during application to the skin. Therefore, changes in the concentration of gelling agents used to achieve suitable consistency and manufacturing and packing processes that meet industrial and marketing requirements do not appear to exert a practical influence on drug availability after application to the skin. 相似文献
993.
994.
995.
The optimization of wet granulation in a 10-liter high-shear mixer was investigated using a nonclassical experimental mixture design. Hydroxypropylmethylcellulose, lactose, cornstarch, and microcrystalline cellulose were used as excipients of the granulate, while polyvinylpyrrolidone was used as binder. Besides the minimization of the number of experiments, the strategy applied takes into account the cost of each experiment. The introduction of such a modification allowed us to select an experimental matrix giving enough information with a relatively low number of experiments and at a minimum cost. 相似文献
996.
997.
M Beresewicz 《Canadian Metallurgical Quarterly》1994,28(4):455-466
The normothymic effect of carbamazepine administered alone or in combination with lithium in patients with affective disorders was studied. The incidence and time-course of carbamazepine-induced side effects was analyzed. 相似文献
998.
999.
The aims of the present study were to analyze the most important chemical reactions between sodium hydroxide and potato constituents involved in potato chemical peeling, and to measure the apparent diffusivity of NaOH in potato skin and flesh separately, as a function of temperature and NaOH concentration, selected according to potato chemical peeling process. Chemical reaction of the suberin of the potato skin with NaOH was proposed as the most important one to promote chemical peeling. Whereas starch hydrolysis, middle lamella dissolution and cell wall disruptions were proposed as the principal chemical reactions in flesh. Experiments to determine NaOH apparent dijfusivities in skin and flesh were performed following a cell diffusion method at 25, 40, 50, 60 and 70 °C temperatures and concentrations of 4, 12 and 20 g NaOH/100 g of solution. Finally, correlation equations were determined to describe apparent diffusivity dependence on temperature and concentration. 相似文献
1000.